<?php
/*=======================================================================
 // File:        JPGRAPH_GRADIENT.PHP
 // Description: Create a color gradient
 // Created:     2003-02-01
 // Ver:         $Id: jpgraph_gradient.php 1761 2009-08-01 08:31:28Z ljp $
 //
 // Copyright (c) Aditus Consulting. All rights reserved.
 //========================================================================
 */

// Styles for gradient color fill
define("GRAD_VER",1);
define("GRAD_VERT",1);
define("GRAD_HOR",2);
define("GRAD_MIDHOR",3);
define("GRAD_MIDVER",4);
define("GRAD_CENTER",5);
define("GRAD_WIDE_MIDVER",6);
define("GRAD_WIDE_MIDHOR",7);
define("GRAD_LEFT_REFLECTION",8);
define("GRAD_RIGHT_REFLECTION",9);
define("GRAD_RAISED_PANEL",10);
define("GRAD_DIAGONAL",11);

//===================================================
// CLASS Gradient
// Description: Handles gradient fills. This is to be
// considered a "friend" class of Class Image.
//===================================================
class Gradient {
	private $img=null, $numcolors=100;
	//---------------
	// CONSTRUCTOR
	function __construct(&$img) {
		$this->img = $img;
	}


	function SetNumColors($aNum) {
		$this->numcolors=$aNum;
	}
	//---------------
	// PUBLIC METHODS
	// Produce a gradient filled rectangle with a smooth transition between
	// two colors.
	// ($xl,$yt)  Top left corner
	// ($xr,$yb) Bottom right
	// $from_color Starting color in gradient
	// $to_color End color in the gradient
	// $style  Which way is the gradient oriented?
	function FilledRectangle($xl,$yt,$xr,$yb,$from_color,$to_color,$style=1) {
		$this->img->SetLineWeight(1);
		switch( $style ) {
			case GRAD_VER:
				$steps = ceil(abs($xr-$xl)+1);
				$delta = $xr>=$xl ? 1 : -1;
				$this->GetColArray($from_color,$to_color,$steps,$colors,$this->numcolors);
				for( $i=0, $x=$xl; $i < $steps; ++$i ) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yt,$x,$yb);
					$x += $delta;
				}
				break;

			case GRAD_HOR:
				$steps = ceil(abs($yb-$yt)+1);
				$delta = $yb >= $yt ? 1 : -1;
				$this->GetColArray($from_color,$to_color,$steps,$colors,$this->numcolors);
				for($i=0,$y=$yt; $i < $steps; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($xl,$y,$xr,$y);
					$y += $delta;
				}
				break;

			case GRAD_MIDHOR:
				$steps = ceil(abs($yb-$yt)/2);
				$delta = $yb >= $yt ? 1 : -1;
				$this->GetColArray($from_color,$to_color,$steps,$colors,$this->numcolors);
				for($y=$yt, $i=0; $i < $steps;  ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($xl,$y,$xr,$y);
					$y += $delta;
				}
				--$i;
				if( abs($yb-$yt) % 2 == 1 ) {
					--$steps;
				}
				for($j=0; $j < $steps; ++$j, --$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($xl,$y,$xr,$y);
					$y += $delta;
				}
				$this->img->Line($xl,$y,$xr,$y);
				break;

			case GRAD_MIDVER:
				$steps = ceil(abs($xr-$xl)/2);
				$delta = $xr>=$xl ? 1 : -1;
				$this->GetColArray($from_color,$to_color,$steps,$colors,$this->numcolors);
				for($x=$xl, $i=0; $i < $steps; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				--$i;
				if( abs($xr-$xl) % 2 == 1 ) {
					--$steps;
				}
				for($j=0; $j < $steps; ++$j, --$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				$this->img->Line($x,$yb,$x,$yt);
				break;

			case GRAD_WIDE_MIDVER:
				$diff = ceil(abs($xr-$xl));
				$steps = floor(abs($diff)/3);
				$firststep = $diff - 2*$steps ;
				$delta = $xr >= $xl ? 1 : -1;
				$this->GetColArray($from_color,$to_color,$firststep,$colors,$this->numcolors);
				for($x=$xl, $i=0; $i < $firststep; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				--$i;
				$this->img->current_color = $colors[$i];
				for($j=0; $j< $steps; ++$j) {
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}

				for($j=0; $j < $steps; ++$j, --$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				break;

			case GRAD_WIDE_MIDHOR:
				$diff = ceil(abs($yb-$yt));
				$steps = floor(abs($diff)/3);
				$firststep = $diff - 2*$steps ;
				$delta = $yb >= $yt? 1 : -1;
				$this->GetColArray($from_color,$to_color,$firststep,$colors,$this->numcolors);
				for($y=$yt, $i=0; $i < $firststep;  ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($xl,$y,$xr,$y);
					$y += $delta;
				}
				--$i;
				$this->img->current_color = $colors[$i];
				for($j=0; $j < $steps; ++$j) {
					$this->img->Line($xl,$y,$xr,$y);
					$y += $delta;
				}
				for($j=0; $j < $steps; ++$j, --$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($xl,$y,$xr,$y);
					$y += $delta;
				}
				break;

			case GRAD_LEFT_REFLECTION:
				$steps1 = ceil(0.3*abs($xr-$xl));
				$delta = $xr>=$xl ? 1 : -1;

				$from_color = $this->img->rgb->Color($from_color);
				$adj = 1.4;
				$m = ($adj-1.0)*(255-min(255,min($from_color[0],min($from_color[1],$from_color[2]))));
				$from_color2 = array(min(255,$from_color[0]+$m),
				min(255,$from_color[1]+$m), min(255,$from_color[2]+$m));

				$this->GetColArray($from_color2,$to_color,$steps1,$colors,$this->numcolors);
				$n = count($colors);
				for($x=$xl, $i=0; $i < $steps1 && $i < $n; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				$steps2 = max(1,ceil(0.08*abs($xr-$xl)));
				$this->img->SetColor($to_color);
				for($j=0; $j< $steps2; ++$j) {
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				$steps = abs($xr-$xl)-$steps1-$steps2;
				$this->GetColArray($to_color,$from_color,$steps,$colors,$this->numcolors);
				$n = count($colors);
				for($i=0; $i < $steps && $i < $n; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				break;

			case GRAD_RIGHT_REFLECTION:
				$steps1 = ceil(0.7*abs($xr-$xl));
				$delta = $xr>=$xl ? 1 : -1;

				$this->GetColArray($from_color,$to_color,$steps1,$colors,$this->numcolors);
				$n = count($colors);
				for($x=$xl, $i=0; $i < $steps1 && $i < $n; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				$steps2 = max(1,ceil(0.08*abs($xr-$xl)));
				$this->img->SetColor($to_color);
				for($j=0; $j< $steps2; ++$j) {
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}

				$from_color = $this->img->rgb->Color($from_color);
				$adj = 1.4;
				$m = ($adj-1.0)*(255-min(255,min($from_color[0],min($from_color[1],$from_color[2]))));
				$from_color = array(min(255,$from_color[0]+$m),
				min(255,$from_color[1]+$m), min(255,$from_color[2]+$m));

				$steps = abs($xr-$xl)-$steps1-$steps2;
				$this->GetColArray($to_color,$from_color,$steps,$colors,$this->numcolors);
				$n = count($colors);
				for($i=0; $i < $steps && $i < $n; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				break;

			case GRAD_CENTER:
				$steps = ceil(min(($yb-$yt)+1,($xr-$xl)+1)/2);
				$this->GetColArray($from_color,$to_color,$steps,$colors,$this->numcolors);
				$dx = ($xr-$xl)/2;
				$dy = ($yb-$yt)/2;
				$x=$xl;$y=$yt;$x2=$xr;$y2=$yb;
				$n = count($colors);
				for($x=$xl, $i=0; $x < $xl+$dx && $y < $yt+$dy && $i < $n; ++$x, ++$y, --$x2, --$y2, ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Rectangle($x,$y,$x2,$y2);
				}
				$this->img->Line($x,$y,$x2,$y2);
				break;

			case GRAD_RAISED_PANEL:
				// right to left
				$steps1 = $xr-$xl;
				$delta = $xr>=$xl ? 1 : -1;
				$this->GetColArray($to_color,$from_color,$steps1,$colors,$this->numcolors);
				$n = count($colors);
				for($x=$xl, $i=0; $i < $steps1 && $i < $n; ++$i) {
					$this->img->current_color = $colors[$i];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}

				// left to right
				$xr -= 3;
				$xl += 3;
				$yb -= 3;
				$yt += 3;
				$steps2 = $xr-$xl;
				$delta = $xr>=$xl ? 1 : -1;
				for($x=$xl, $j=$steps2; $j >= 0; --$j) {
					$this->img->current_color = $colors[$j];
					$this->img->Line($x,$yb,$x,$yt);
					$x += $delta;
				}
				break;

			case GRAD_DIAGONAL:
				// use the longer dimension to determine the required number of steps.
				// first loop draws from one corner to the mid-diagonal and the second
				// loop draws from the mid-diagonal to the opposing corner.
				if($xr-$xl > $yb - $yt) {
					// width is greater than height -> use x-dimension for steps
					$steps = $xr-$xl;
					$delta = $xr>=$xl ? 1 : -1;
					$this->GetColArray($from_color,$to_color,$steps*2,$colors,$this->numcolors);
					$n = count($colors);

					for($x=$xl, $i=0; $i < $steps && $i < $n; ++$i) {
						$this->img->current_color = $colors[$i];
						$y = $yt+($i/$steps)*($yb-$yt)*$delta;
						$this->img->Line($x,$yt,$xl,$y);
						$x += $delta;
					}

					for($x=$xl, $i = 0; $i < $steps && $i < $n; ++$i) {
						$this->img->current_color = $colors[$steps+$i];
						$y = $yt+($i/$steps)*($yb-$yt)*$delta;
						$this->img->Line($x,$yb,$xr,$y);
						$x += $delta;
					}
				} else {
					// height is greater than width -> use y-dimension for steps
					$steps = $yb-$yt;
					$delta = $yb>=$yt ? 1 : -1;
					$this->GetColArray($from_color,$to_color,$steps*2,$colors,$this->numcolors);
					$n = count($colors);

					for($y=$yt, $i=0; $i < $steps && $i < $n; ++$i) {
						$this->img->current_color = $colors[$i];
						$x = $xl+($i/$steps)*($xr-$xl)*$delta;
						$this->img->Line($x,$yt,$xl,$y);
						$y += $delta;
					}

					for($y=$yt, $i = 0; $i < $steps && $i < $n; ++$i) {
						$this->img->current_color = $colors[$steps+$i];
						$x = $xl+($i/$steps)*($xr-$xl)*$delta;
						$this->img->Line($x,$yb,$xr,$y);
						$x += $delta;
					}

				}
				break;

			default:
				JpGraphError::RaiseL(7001,$style);
				//("Unknown gradient style (=$style).");
				break;
		}
	}

	// Fill a special case of a polygon with a flat bottom
	// with a gradient. Can be used for filled line plots.
	// Please note that this is NOT a generic gradient polygon fill
	// routine. It assumes that the bottom is flat (like a drawing
	// of a mountain)
	function FilledFlatPolygon($pts,$from_color,$to_color) {
		if( count($pts) == 0 ) return;

		$maxy=$pts[1];
		$miny=$pts[1];
		$n = count($pts) ;
		for( $i=0, $idx=0; $i < $n; $i += 2) {
			$x = round($pts[$i]);
			$y = round($pts[$i+1]);
			$miny = min($miny,$y);
			$maxy = max($maxy,$y);
		}

		$colors = array();
		$this->GetColArray($from_color,$to_color,abs($maxy-$miny)+1,$colors,$this->numcolors);
		for($i=$miny, $idx=0; $i <= $maxy; ++$i ) {
			$colmap[$i] = $colors[$idx++];
		}

		$n = count($pts)/2 ;
		$idx = 0 ;
		while( $idx < $n-1 ) {
			$p1 = array(round($pts[$idx*2]),round($pts[$idx*2+1]));
			$p2 = array(round($pts[++$idx*2]),round($pts[$idx*2+1]));

			// Find the largest rectangle we can fill
			$y = max($p1[1],$p2[1]) ;
			for($yy=$maxy; $yy > $y; --$yy) {
				$this->img->current_color = $colmap[$yy];
				$this->img->Line($p1[0],$yy,$p2[0]-1,$yy);
			}

			if( $p1[1] == $p2[1] ) {
				continue;
			}

			// Fill the rest using lines (slow...)
			$slope = ($p2[0]-$p1[0])/($p1[1]-$p2[1]);
			$x1 = $p1[0];
			$x2 = $p2[0]-1;
			$start = $y;
			if( $p1[1] > $p2[1] ) {
				while( $y >= $p2[1] ) {
					$x1=$slope*($start-$y)+$p1[0];
					$this->img->current_color = $colmap[$y];
					$this->img->Line($x1,$y,$x2,$y);
					--$y;
				}
			}
			else {
				while( $y >= $p1[1] ) {
					$x2=$p2[0]+$slope*($start-$y);
					$this->img->current_color = $colmap[$y];
					$this->img->Line($x1,$y,$x2,$y);
					--$y;
				}
			}
		}
	}

	//---------------
	// PRIVATE METHODS
	// Add to the image color map the necessary colors to do the transition
	// between the two colors using $numcolors intermediate colors
	function GetColArray($from_color,$to_color,$arr_size,&$colors,$numcols=100) {
		if( $arr_size==0 ) {
			return;
		}

		// If color is given as text get it's corresponding r,g,b values
		$from_color = $this->img->rgb->Color($from_color);
		$to_color = $this->img->rgb->Color($to_color);

		$rdelta=($to_color[0]-$from_color[0])/$numcols;
		$gdelta=($to_color[1]-$from_color[1])/$numcols;
		$bdelta=($to_color[2]-$from_color[2])/$numcols;
		$colorsperstep = $numcols/$arr_size;
		$prevcolnum = -1;
		$from_alpha = $from_color[3];
		$to_alpha = $to_color[3];
		$adelta = ( $to_alpha - $from_alpha ) / $numcols ;
		for ($i=0; $i < $arr_size; ++$i) {
			$colnum = floor($colorsperstep*$i);
			if ( $colnum == $prevcolnum ) {
				$colors[$i] = $colidx;
			}
			else {
				$r = floor($from_color[0] + $colnum*$rdelta);
				$g = floor($from_color[1] + $colnum*$gdelta);
				$b = floor($from_color[2] + $colnum*$bdelta);
				$alpha = $from_alpha + $colnum*$adelta;
				$colidx = $this->img->rgb->Allocate(sprintf("#%02x%02x%02x",$r,$g,$b),$alpha);
				$colors[$i] = $colidx;
			}
			$prevcolnum = $colnum;
		}
	}
} // Class

?>
